Navigating introducer for tissue access system

ABSTRACT

A surgical access system is disclosed that includes an outer sheath, an introducer, and a navigational stylet. The outer sheath is defined by an open distal end and an open proximal end and includes a hollow body portion therebetween. The obturator is defined by a distal end and a proximal end. The distal end further comprises a tapered distal tip member that terminates in a distal tip. The navigational stylet is configured to be selectively fixed to the obturator and is configured to indicate the location of the obturator within a patient during use. The obturator is configured to be received within the outer sheath such that the tapered distal tip member protrudes from the open distal end of the outer sheath when the obturator is in an introducing configuration.

TECHNICAL FIELD

The present disclosure relates to a tissue access system that cooperateswith a navigation system.

BACKGROUND

Diagnosis and treatment of conditions affecting the brain are among themost difficult and complex problems that face the medical profession.The brain is a complex and delicate soft multi-component tissuestructure that receives multiple inputs, processes these inputs,responds to the inputs and controls bodily functions through a complexneural network connected to the rest of the body through the spinalcord. The brain and spinal cord are contained within and protected bysignificant bony structures, e.g., the skull and the spine. Given thedifficulty of safely accessing the areas of the brain housed within thehard bony protective skull, as well as navigating the delicate networkand complex interactions that form the neural communication networkcontained within the brain that define the human body's ability to carryon its functions of speech, sight, hearing, functional mobility,reasoning, emotions, respiration and other metabolic functions, thediagnosis and treatment of brain disorders presents unique challengesnot encountered elsewhere in the body.

For example, abnormalities such as intracranial cerebral hematomas(ICH), abscesses, glioblastomas (GB), metastases (mets) and functionaldiseases manifest themselves in the intraparenchymal subcortical space(i.e., the white matter) of the brain are particularly challenging toaccess, let alone treat. The white matter and the cortex containeloquent communication structures (neural network) which are located inthe subcortical space, called fiber tracts and fascicles which make upthe fascicular anatomy. Thus, traditionally, unless the ICH, GB, and/ormets were considered anything but “superficial,” such conditions havebeen considered challenging to access or inoperable, simply becausegetting to the abnormality ICH, GB and/or mets are considered just asdamaging as letting the condition take its course. Similarly, tissueabnormalities such as tumors, cysts and fibrous membrane growths whichmanifest within the intraventricular space of the brain are consideredchallenging to safely access and often inoperable, due to theirlocations within the brain and the eloquent real estate that must betraversed to access them.

In order to assist in diagnosis and subsequent treatment of braindisorders, clear, accurate imaging of brain tissue through the skull isrequired. In recent years significant advances have been made in imagingtechnology, including stereotactic X-ray imaging, Computerized AxialTomography (CAT), Computerized Tomographic Angiography (CTA), PositionEmission Tomography (PET) and Magnetic Resonance Imaging (MRI),sequences such as Diffusion Tensor Imaging (DTI) and Diffusion WeightedImages (DWI). Navigation systems (instrument position tracking systems)have also been improved to allow for the input of many of these improvedimaging sequences such as CT and MRI to allow for improved accuracy whentracking instruments within the human body with the informationdownloaded to the navigational system from these imaging systemsequences. These imaging devices and techniques permit the surgeon toobserve conditions within the brain in a non-invasive manner withoutopening the skull, as well as provide a map of critical structuressurrounding an area of interest, including structures such as bloodvessels, membranes, tumor margins, cranial nerves, including thefascicular anatomy. If an abnormality is identified through the use ofone or more imaging modalities and/or techniques, it may be necessary ordesirable to biopsy or remove the abnormality. The navigational systemallows for the intraoperative translation of these sequences during aprocedure so that the user may maintain their intraoperative locationand orientation during the case.

Once a course of action has been determined based upon one or moreimaging techniques, a surgical treatment may be necessary or desired. Inorder to operate surgically on the brain, access must be obtainedthrough the skull and eleoquent brain tissue containing blood vesselsand nerves that can be adversely affected by even slight disturbances.Therefore, great care must be taken when traversing the internalcorridor and operating on the brain so as not to disturb delicate bloodvessels and nerves to prevent adverse consequences resulting from asurgical intervention.

Traditionally, accessing abnormalities which manifest in deeper spaceswithin the brain has meant a need for a surgery that creates a highlyinvasive approach. In some instances, in order to obtain access totarget tissue, a substantial portion of the skull is removed and entiresections of the brain are retracted or removed to obtain access todeliver optics, light and instrumentation. For example, surgical brainretractors are used to pull apart or spread delicate brain tissue, whichcan leave pressure marks from lateral edges of the retractor. In someinstances, a complication known as “retraction injury” may occur due touse of brain retractors. Of course, such techniques are not appropriatefor all situations, and not all patients are able to tolerate andrecover from such tissue disruptive invasive techniques.

It is also known to access certain portions of the brain by creating aburr hole craniotomy, but only limited surgical techniques may beperformed through such smaller openings. In addition, some techniqueshave been developed to enter through the nasal passages, opening anaccess hole through the occipital bone to remove tumors located, forexample, in the area of the pituitary, such as skull base tumors.

A significant advance in brain surgery is stereotactic surgery involvinga stereotactic frame correlated to stereotactic X-ray images to guide anavigational system probe or other surgical instrument through anopening formed in the skull through brain tissue to a target lesion orother body. A related advance is frameless image guidance, in which animage of the surgical instrument is superimposed on a pre-operativeimage to demonstrate the location of the instrument to the surgeon andtrajectory of further movement of the probe or instrument on or withinthe skull.

While minimally invasive and non-disruptive access systems have beendeveloped now to provide access to previously difficult to access orwhat were previously considered inoperable areas in the brain and spine,many such access systems do not have the capability to providenavigational information during positioning of the access system.

Notwithstanding the foregoing advances in navigation technology of bothframe and frameless stereotactic image guidance techniques, thereremains a need for improved instrumentation of these navigationalsystems which allows for the use with new advances in minimally invasiveaccess systems.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments of the present disclosure will now be described ingreater detail with reference to the attached figures, in which:

FIG. 1 is an exemplary introducer element of a surgical access system;

FIG. 2A is a perspective view of an outer sheath of a surgical accesssystem;

FIG. 2B is a side elevational view of the outer sheath of FIG. 2A;

FIG. 2C is an end view of the outer sheath of FIG. 2A;

FIG. 3A is a cross-sectional view of a navigational stylet positionedwithin a first exemplary introducer element of a surgical access system;

FIG. 3B is a cross-sectional view of a navigational stylet positionedwithin a second exemplary introducer element of a surgical accesssystems;

FIG. 4 is a perspective view a surgical access system with analternative arrangement of the introducer element disposed in the outersheath and the navigational stylet positioned within the introducerelement; and

FIG. 5 is an enlarged view of a distal end of the surgical access systemtaken from area 5 in FIG. 4.

DETAILED DESCRIPTION

Referring now to the discussion that follows and also to the drawings,illustrative approaches to the disclosed assemblies and methods areshown in detail. Although the drawings represent some possibleapproaches, the drawings are not necessarily to scale and certainfeatures may be exaggerated, removed, or partially sectioned to betterillustrate and explain the present disclosure. Further, the descriptionsset forth herein are not intended to be exhaustive or otherwise limit orrestrict the claims to the precise forms and configurations shown in thedrawings and disclosed in the following detailed description.

Described herein is surgical access assembly, various components for usein same, and a method of using the surgical access assembly. Thecomponents disclosed herein provide surgeons with an enhanced ability tominimize trauma to the patient, while providing efficient improvedminimally invasive surgical techniques, such as, for example, duringintracranial surgical techniques. The components disclosed herein mayfurther be used for application of targeted and effective treatmentregimens. The surgical access assembly disclosed herein may includecomponents similar to those shown in copending U.S. application Ser. No.13/444,732, the contents of which are incorporated by reference in itsentirety.

Generally, a surgical access system 10 (best seen in FIG. 4) of thepresent disclosure may comprise an introducer 12 (FIG. 1) and an outersheath 14 (FIGS. 2A-2C). The introducer 12 is configured with a lengththat is longer than a length of outer sheath 12 such that a distal endof the introducer 12 protrudes a predetermined distance from a distalend of the outer sheath 14, as will be discussed below in greaterdetail. A stylet with a navigational element 16 may also be used withthe surgical access system 10. A locking member 18 may also be providedto selectively lock the stylet 16 to the introducer 16, as will beexplained in further detail below.

Turning to FIG. 1, an exemplary arrangement of an introducer 12 isillustrated. Introducer 12 is defined by distal end 20, a proximal end22, and a body portion 24. A handle portion 26 may be fixedly secured tothe proximal end 22. The handle portion 26 may include a texturedgripping element 27 to assist in gripping the introducer 12. The bodyportion 24 is generally solid, with a narrow channel 50 disposedtherein.

Distal end 20 is configured with a generally conical shaped distal tipportion 28 that tapers from the body portion 24 toward the distal end20. In one exemplary arrangement, a distal end 32 of the navigationalstylet 16 extends through a distal opening 30 of the introducer 12. Withthis configuration, the conical shaped distal tip portion 28 cooperateswith a non-blunt or non-sharpened distal end 32 of the navigationalstylet 16 to provide dilation of tissue, as the surgical access system10 is directed through brain tissue.

In an alternative exemplary arrangement, distal tip portion 28 taperstoward a closed tip member 31 (as best seen in FIGS. 3A and 3B) so as toprevent coring of tissue as introducer is inserted into the brain. Inthis arrangement, the distal end 32 of the navigational stylet 16 isoffset from the distal tip 28′ by a predetermined distance, as will beexplained in further detail below.

There are a number of variables that play the selection of the angle αthat defines the taper of tip portion 28. These variables include thesize of an outer diameter D1 of the introducer 12, the desired lengththat distal tip portion 28 extends from the body portion 24, and thedesired offset for a distal end 32 of the navigational stylet 16 and tipmember 28. More specifically, it is contemplated that surgical accessassembly 10 will be provided as part of a kit that may include multiplesized outer sheaths 14 and introducers 12, to provide the surgeon with achoice of different diameter sizes and lengths so as to provideflexibility for accessing areas of interest within the brain. However,to insure that the distal tip 31 is determinable regardless of whichsize diameter D1 of introducer 12 is used, taper angle α may beselectively adjusted. For embodiments that utilize navigation stylet 16that seats a distal end thereof at a set position within the introducer12, to maintain an identical offset length between the distal end 32 ofnavigation stylet 16 and distal tip 31 in different diameter D1 sizedintroducers 12, taper angle α will need to be increased, as diameter D1increases.

The distal tip 31 is configured to be radiused such that tip member 31is rounded, and neither blunt, nor sharp. More specifically, tip member31 is configured so as not to have any flat portions which duringinsertion can stretch or even tear the delicate tissues such as thevessels, fiber tracts and fascicles found in the brain. Further, becausetip member 31 is closed, damage of such delicate tissues and fasciclesare also avoided. In the arrangement where the navigational stylet 16extends through the distal opening 30, the distal end 32 of thenavigational stylet 16 may also be configured so as not to have any flatportions. Further, the distal end 32 of the navigational stylet 16 mayalso have a tapered section 34 that mates with the tapered tip member 28to provide a smooth transition between the introducer 12 and thenavigational stylet 16, as shown in FIG. 5. The configuration of tipmember 28 is designed to gently displace and move the tissue into whichit is inserted; i.e., atraumatically dilate the tissue to allow forintroduction in to an intra-fascicular and para-fascicular manner, asopposed to cutting tissue as surgical access assembly 10 is insertedinto the tissue.

Referring to FIGS. 2A-2C, an exemplary embodiment of the outer sheath 14is shown. The outer sheath 14 is defined by distal end 34 and a proximalend 36 and includes a generally hollow body portion 38. While not shown,outer sheath 14 may also be configured with a grip portion, such as thatshown in co-pending U.S. application Ser. No. 13/444,732. In oneexemplary arrangement, body portion 38 is constructed of a clearbiocompatible material that permits viewing of normal tissue, abnormaltissue, as well as critical structures that are disposed outside of bodyportion 38 when outer sheath 12 is disposed within such tissue. In oneexemplary arrangement, outer sheath 12 is constructed of polycarbonate,though other biocompatible materials may be employed, including resins.Further, the body portion 38 may also be constructed of a non-reflectivematerial so as to reduce eye-fatigue for the surgeon.

Distal end 34 of the outer sheath 14 may be configured with a taperedportion 40 that extends towards a center axis A-A of the outer sheath 14to a distal edge 42 that surrounds an opening in the distal end 34 ofthe outer sheath 14. Tapered portion 40 serves to ease the transitionbetween the outer sheath 14 and a distal tip portion 40, without drag,trauma or coring of tissue from a diameter that defines the body portion24 of the introducer 12 to a diameter that defines the body portion 38of the outer sheath 14. In one exemplary configuration, distal end 34may be configured with a radius or other configuration so as to create asmooth/atraumatic transition of the brain tissue when surgical accessassembly 10 is inserted into the brain.

Referring to FIGS. 3A and 3B, the navigational stylet 16 includes adistal tip 32 and an elongated body portion. The elongated body portionhas a proximal end 46 operatively connected to a navigational element48, as shown in FIG. 4. In one exemplary arrangement, the elongated bodyportion of the stylet 16 is offset such that the navigational element 48is out of the line of site of the operator during insertion of thesurgical access system. The navigational stylet 16 is removablypositioned within the channel 50 formed through the introducer 12. Asdiscussed above, in one exemplary arrangement, the channel 50 is narrowso as only to be slightly larger than the diameter of the navigationalstylet 16. With this arrangement, the relative position of the stylet 16within in the introducer is maintained as the channel 50 may serve as analignment feature for the stylet 16 with respect to the distal tip 31 ofthe introducer. In the exemplary configuration shown in FIGS. 3A and 3B,the distal tip 32 of the navigational stylet 16 may be seated adjacent adistal tip 31 of the introducer 12. More specifically, the channel 50may terminate with an inwardly directing seat, which is complementary tothe taper configuration of the distal tip 32 to insure proper placementof the navigational stylet 16 within the introducer 12. As discussedabove, the predetermined offset from the distal tip 31 of the introducerand the distal tip 32 of the navigational stylet 16 may be programmedinto a navigational system to allow the user to know where the distaltip of introducer 12 is during movement of the surgical access system toan area of interest in the patient. In the embodiment of FIGS. 4 and 5,the distal tip 32 of the navigational stylet 16 is configured to extendthrough the opening 30 of the introducer 12 so as to protrude throughthe opening 30.

In use, the navigational stylet 16 is inserted into the channel 50 ofthe introducer 12. In one exemplary arrangement, the navigational stylet16 may be provided with depth markers (not shown) on the outsidesurface. The depth markers serve as a reference to a user to indicatehow far the navigational stylet is inserted into the introducer andsubsequently how far the stylet protrudes from the introducer, for thearrangement shown in FIG. 5. In use, the operator cannot see the distaltip of the introducer. Thus, having a reference point is verybeneficial. To maintain the navigational stylet 16 in position, therebynot requiring a user to hold the navigational stylet 16 in positionduring the introduction of the surgical access assembly 10 to an area ofinterest, in one exemplary arrangement, a locking member 18 may beprovided to lock the introducer 12 to the navigational stylet 16. In oneexemplary arrangement, a touhy-borst connector may serve as the lockingmember 18. The touhy-borst connector will also serve as a depth stop toprevent damage to the distal tip 32 of the navigational stylet 16.

In an alternative arrangement, the introducer 12 may further comprise anopening (not shown) positioned adjacent the proximal end 22 of theintroducer 12 or through the handle portion 26. A set screw (not shown)may be directed through the opening to contact the navigational stylet16 and retain the navigational stylet 16 to the introducer 12, asdisclosed in copending U.S. application Ser. No. 13/444,732.

Once the navigational stylet 16 is selectively attached to theintroducer 12, the outer sheath 14 is positioned over the introducer 12until the tapered tip member 28 extends distally from the taperedportion 40 of the outer sheath 14. Once the outer sheath 14 ispositioned on the introducer 12, the surgical access system 10 may bedirected into brain tissue to a location of interest. Due to theconfiguration of the distal tips 31/32, brain tissue is atraumaticallypushed away from the surgical access system 10, without causing unduedamage to the tissue.

Once the navigational stylet 16 indicates that the location of interesthas been reached, the introducer 12 may then be removed from the outersheath 14, while leaving the outer sheath 14 in place. The outer sheath14 will then serve as an access pathway to an area of interest.

With regard to the processes, systems, methods, heuristics, etc.described herein, it should be understood that, although the steps ofsuch processes, etc. have been described as occurring according to acertain ordered sequence, such processes could be practiced with thedescribed steps performed in an order other than the order describedherein. It further should be understood that certain steps could beperformed simultaneously, that other steps could be added, or thatcertain steps described herein could be omitted. In other words, thedescriptions of processes herein are provided for the purpose ofillustrating certain embodiments, and should in no way be construed soas to limit the claims.

Accordingly, it is to be understood that the above description isintended to be illustrative and not restrictive. Many embodiments andapplications other than the examples provided would be apparent uponreading the above description. The scope should be determined, not withreference to the above description, but should instead be determinedwith reference to the appended claims, along with the full scope ofequivalents to which such claims are entitled. It is anticipated andintended that future developments will occur in the technologiesdiscussed herein, and that the disclosed systems and methods will beincorporated into such future embodiments. In sum, it should beunderstood that the application is capable of modification andvariation.

All terms used in the claims are intended to be given their broadestreasonable constructions and their ordinary meanings as understood bythose knowledgeable in the technologies described herein unless anexplicit indication to the contrary in made herein. In particular, useof the singular articles such as “a,” “the,” “said,” etc. should be readto recite one or more of the indicated elements unless a claim recitesan explicit limitation to the contrary.

What is claimed is:
 1. A surgical access system, comprising: an outersheath defined by an open distal end and an open proximal end andincluding a hollow body portion therebetween; an introducer defined by adistal end and a proximal end, wherein the distal end further comprisesa tapered distal tip member that terminates in a distal tip, wherein theintroducer further comprises a channel disposed through the introducerand the channel terminates in an inwardly tapered distal end spacedproximally from the distal tip; and a navigational stylet selectivelypositioned within the inwardly tapered distal end of the channel so asto receive the distal end of the navigational element therein spacedfrom the distal tip of the introducer, when the navigational element isin an introducing configuration; wherein the navigational stylet isconfigured to indicate a location of the introducer within a patientduring use; wherein the introducer is configured to be received withinthe outer sheath such that the tapered distal tip member protrudes fromthe open distal end of the outer sheath when the introducer is in theintroducing configuration.
 2. The surgical access system of claim 1,wherein the distal end of the introducer has a conical shape.
 3. Thesurgical access system of claim 1, wherein the navigational styletfurther comprises depth markers.
 4. The surgical access system of claim1, further comprising a locking member configured to retain theintroducer to the navigational element stylet while in the introductionconfiguration.
 5. The surgical access system of claim 4, wherein thelocking member is a touhy-borst connector.
 6. The surgical access systemof claim 1, wherein the channel is centered within the introducer so asto center the navigational stylet within the introducer.
 7. The surgicalaccess system of claim 1, wherein the navigational stylet has a bodyportion with an offset such that the navigational element is offset fromthe introducer when the stylet is positioned within the channel.
 8. Thesurgical access system of claim 1, wherein the outer sheath furtherincludes a tapered section positioned at the distal end of the outersheath.